The impact of whole-body cryotherapy on core- and muscle temperature
9 May 2020 / 0 comments


Whole-body cryotherapy: do you get the shivers?


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It might make you shiver just thinking about experiencing temperatures of -130°C/-202ºF) for several minutes.

In this blog, we explain the effect of whole-body cryotherapy on core and muscle temperatures.

What is core temperature?

This is the typical temperature range found in humans. The normal range is usually stated as [36.5 – 37.5ºC]/[97.7 – 99.5ºF. This temperature depends upon many factors such as age, whether the body is fighting infection, gender, activity, etc. The core temperature at rest is typically maintained within this range by thermoregulation. Maintaining core temperature is essential for all kinds of processes throughout the body and therefore essential for survival. The body has several ways to maintain core temperature. For example, we can increase our sweat rate when the core temperature is elevated, and our body starts shivering when the core temperature is reduced too quickly.

What is muscle temperature?

It is the temperature measured in the muscle tissue. The typical range for muscle temperature at rest is a little below the core temperature range 34 – 36ºC/ [93.2 – 96.8ºF] and depends on the depth of measurement: the deeper you measure the closer it is to the core temperature. In practice, muscle temperature is assessed with a thermal probe and can be measured, depending on the site, at different tissue depths (up to a maximum of 4cm/1.6inch of depth approximately). Everything in life requires energy, this energy is extracted from our nutrition, a side product of this process is heat.

Heat causes, among others, the muscle temperature to increase – a change that can be up to a few degrees. Like the core temperature, muscle temperature is also maintained within a safe range in order to keep it functioning correctly.

Core- and muscle temperature interact and work together. For example, during exercise, more energy is needed and thus more heat is produced, causing the core and muscle temperatures to increase. This increase is assessed by our thermoregulatory center (within the hypothalamus), responding with an increase in sweat rate to cool down and maintain core and muscle temperature.


What does whole-body cryotherapy do to your core- and muscle temperatures?


Unfortunately, not much experimental data is available concerning whole- body cryotherapy exposure and its effect on core- and in particular muscle temperature. This may be due to ethical challenges and the high costs involved when using invasive techniques like measuring muscle temperatures. However, scientific studies published illustrate consistent results. Both core- and muscle temperatures are reduced by a whole body cryotherapy session.

Core temperature undergoes a drop in the range of [0–0.3°C] / [0–0.54°F)], which although seemingly small, appears to be significant as recorded in most studies (Westerlund et al 2003Costello et al. 2012Zalewski et al. 2014). The maximum decrease in core temperature is observed 50 to 60 minutes after a whole-body cryotherapy session (Zalewski et al. 2014). The effect on muscle temperature depends on the measurement depth. For example, at 2 cm/0.8 inch depth, the temperature is reduced in the range of [1.2–1.9°C]/[2.2 – 3.4°F] 10 minutes after exposure (Costello et al. 2012Mawhinney et al. 2017). In deeper tissue (>3cm/1.2inch depth), a delay of up to 60 minutes is observed before maximum temperature reduction is reached.

One study (Costello et al. 2012) compared 4-minute whole-body cryotherapy at -110°C/-166°F) session with a 4-minute cold water immersion session with respect to the effect on core- and muscle temperatures. It demonstrated that a single whole-body cryotherapy exposure decreases core and muscle temperatures to a similar extent to that experienced after cold water immersion.

Is a sudden drop in core and muscle temperatures after whole-body cryotherapy harmful?


Although whole-body cryotherapy has a significant effect on both core- and muscle temperatures, this is in most cases not the primary purpose of the exposure. The main focus of whole-body cryotherapy is to reduce skin temperature. It is important to understand that although there is a significant reduction in both core- and muscle temperature, our body is perfectly capable of coping with the magnitude of these changes. 

References

  • Costello, J. T., Culligan, K., Selfe, J. & Donnelly, A. E. Muscle, skin and core temperature after -110°c cold air and 8°c water treatment. PLoS ONE 7, e48190 (2012).
  • Mawhinney, C. et al. Cold-Water Mediates Greater Reductions in Limb Blood Flow than Whole Body Cryotherapy. Med Sci Sports Exerc (2017). doi:10.1249/MSS.0000000000001223
  • Westerlund, T., Oksa, J., Smolander, J. & Mikkelsson, M. Thermal responses during and after whole-body cryotherapy (−110°C). Journal of Thermal Biology 28, 601–608 (2003).
  • Zalewski, P. et al. Whole-body cryostimulation increases parasympathetic outflow and decreases core body temperature. Therm. Biol. 45, 75–80 (2014).
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